a) Field of the Invention
The present invention relates to an arrangement of a pulley oil passage for a vehicular belt-type continuously variable transmission which improves a workability of the pulley oil passage.
b) Description of the Related Art
A Japanese Patent Application First Publication No. Heisei 8-14378 published on Jan. 16, 1996 exemplifies movable sheave drive mechanism and pulley oil passage structures of a previously proposed belt type continuously variable transmission.
In the previously proposed belt-type continuously variable transmission disclosed in the above-identified Japanese Patent Application First Publication, a movable sheave is restrained on an axle member so as to be enabled to be moved only in an axial direction of the axle member by means of a ball spline. A supply of a pressurized working fluid toward a fluid pressure cylinder chamber formed on a rear surface side of the movable sheave causes the movable sheave to be moved toward an opposing stationary sheave. The movable sheave is biased so as to be approached to the stationary sheave by means of a coil spring having one end fixed onto a seat portion of the movable sheave formed with a step portion located on the rear surface of the movable sheave within the working fluid cylinder chamber.
The pressurized working fluid is supplied within the working fluid chamber cylinder via an axle member axially extended oil passage, an axle member radially extended oil passage, and a pulley oil passage. The axle member axially extended oil passage is extended along the axial direction from a center of the axle member. The axle member radially extended oil passage is extended along a radial direction of the axle member from a tip of the axle member axially extended oil passage. The pulley oil passage, as described above, is disposed on the step portion of the movable sheave having a sufficiently thick wall thickness and an axial center of the pulley oil passage is slightly obliquely slanted to the radial direction of the axle member.
It is noted that although another previously proposed belt-type continuously variable transmission is provided with such a pulley movement mechanism as that within the movable sheave in which the coil spring is not disposed within the working fluid pressure cylinder chamber, its oil passage formed on the movable sheave is obliquely slanted through the step portion of the movable sheave.